Following a single dose of two MINOCIN® 100 mg pellet-filled capsules administered
to 18 normal fasting adult volunteers, maximum serum concentrations were attained
in 1 to 4 hours (average 2.1 hours) and ranged from 2.1 to 5.1 µg/mL (average
3.5 µg/mL). The serum half-life in the normal volunteers ranged from 11.1 to
22.1 hours (average 15.5 hours).
When MINOCIN® Pellet-Filled Capsules were given concomitantly with a high-fat
meal, which included dairy products, the extent of absorption of MINOCIN®
Pellet-Filled Capsules was unchanged compared to dosing under fasting conditions
The mean TMAX was delayed by one hour when administered with food, compared
to dosing under fasting conditions. MINOCIN® Pellet-Filled Capsules may
be administered with or without food.
In previous studies with other minocycline dosage forms, the minocycline serum
half-life ranged from 11 to 16 hours in 7 patients with hepatic dysfunction,
and from 18 to 69 hours in 5 patients with renal dysfunction. The urinary and
fecal recovery of minocycline when administered to 12 normal volunteers was
one-half to one-third that of other tetracyclines.
Microbiology
The tetracyclines are primarily bacteriostatic and are thought to exert their
antimicrobial effect by the inhibition of protein synthesis. The tetracyclines,
including minocycline, have a similar antimicrobial spectrum of activity against
a wide range of gram-positive and gram-negative organisms. Cross-resistance
of these organisms to tetracycline is common. Minocycline has been shown to
be active against most strains of the following microorganisms, both in vitro
and in clinical infections as described in the INDICATIONS
section:
Aerobic Gram-Positive Microorganisms
Because many strains of the following gram-positive microorganisms have been
shown to be resistant to tetracyclines, culture and susceptibility testing are
especially recommended. Tetracycline antibiotics should not be used for streptococcal
diseases unless the organism has been demonstrated to be susceptible. Tetracyclines
are not the drug of choice in the treatment of any type of staphylococcal infection.
Bacillus anthracis1
Listeria monocytogenes1
Staphylococcus aureus
Streptococcus pneumoniae
Aerobic Gram-Negative Microorganisms
Bartonella bacilliformis
Brucella species
Calymmatobacterium granulomatis
Campylobacter fetus
Francisella tularensis
Haemophilus ducreyi
Vibrio cholerae
Yersinia pestis
Because many strains of the following groups of gram-negative microorganisms have been shown to be resistant to tetracyclines, culture and susceptibility tests are especially recommended.
Acinetobacter species
Enterobacter aerogenes
Escherichia coli
Haemophilus influenzae
Klebsiella species
Neisseria gonorrhoeae1
Neisseria meningitidis1
Shigella species
"Other" Microorganisms
Actinomyces species1
Borrelia recurrentis
Chlamydia psittaci
Chlamydia trachomatis
Clostridium species1
Entamoeba species
Fusobacterium nucleatum subspecies fusiforme1
Mycobacterium marinum
Mycoplasma pneumoniae
Propionibacterium acnes
Rickettsiae
Treponema pallidum subspecies pallidum1
Treponema pallidum subspecies pertenue1
Ureaplasma urealyticum
1When penicillin is contraindicated, tetracyclines are alternative
drugs in the treatment of infections caused by the cited microorganisms.
Susceptibility Tests
Susceptibility testing should be performed with tetracycline since it predicts
susceptibility to minocycline. However, certain organisms (eg, some staphylococci
and Acinetobacter species) may be more susceptible to minocycline and
doxycycline than to tetracycline.
Dilution techniques
Quantitative methods are used to determine antimicrobial minimal inhibitory
concentrations (MICs). These MICs provide estimates of the susceptibility of
bacteria to antimicrobial compounds. The MICs should be determined using a standardized
procedure. Standardized procedures are based on a dilution method (Ref1, Ref30
(broth or agar) or equivalent with standardized inoculum concentrations and
standardized concentrations of tetracycline powder. The MIC values should be
interpreted according to the following criteria:
For testing aerobic gram-negative microorganisms (Enterobacteriaceae), Acinetobacter
species and Staphylococcus aureus:
| MIC (µg/mL) |
Interpretation |
| ≤ 4.0 |
Susceptible (S) |
| 8.0 |
Intermediate (I) |
| ≥ 16.0 |
Resistant (R) |
| For testing Haemophilus influenzae2 and
Streptococcus pneumoniae3: |
| MIC (µg/mL) |
Interpretation |
| ≤ 2.0 |
Susceptible (S) |
| 4.0 |
Intermediate (I) |
| ≥ 8.0 |
Resistant (R) |
2 These interpretative standards are applicable
only to broth microdilution susceptibility testing with Haemophilus influenzae
using Haemophilus Test Medium.Ref1
3 These interpretative standards are applicable only to broth microdilution
susceptibility testing using cation- adjusted Muller-Hinton broth with 2-5%
lysed horse blood.1 |
For testing Neisseria gonorrhoeae4:
| MIC (µg/mL) |
Interpretation |
| ≤ 0.25 |
Susceptible (S) |
| 0.5-1.0 |
Intermediate (I) |
| ≥ 2.0 |
Resistant (R) |
| 4 These interpretative standards are applicable
only to agar dilution susceptibility testing using GC agar base and 1% defined
growth supplements.Ref1 |
A report of "Susceptible" indicates that the pathogen is likely to be inhibited
if the antimicrobial compound in the blood reaches the concentrations usually
achievable. A report of "Intermediate" indicates that the result should be considered
equivocal, and, if the microorganism is not fully susceptible to alternative,
clinically feasible drugs, the test should be repeated. This category implies
possible clinical applicability in body sites where the drug is physiologically
concentrated or in situations where high dosage of drug can be used. This category
also provides a buffer zone which prevents small uncontrolled technical factors
from causing major discrepancies in interpretation. A report of "Resistant"
indicates that the pathogen is not likely to be inhibited if the antimicrobial
compound in the blood reaches the concentrations usually achievable; other therapy
should be selected.
Standardized susceptibility test procedures require the use of laboratory control
microorganisms to control the technical aspects of the laboratory procedures.
Standard tetracycline powder should provide the following MIC values:
| Microorganism |
MIC Range (µg/mL) |
| Escherichia coli ATCC 25922 |
0.5-2.0 |
| Enterococcus faecalis ATC 29212 |
8.0-32.0 |
| Staphylococcus aureus ATCC 29213 |
0.25-1.0 |
| Haemophilus influenzae ATCC 49247 |
4.0-32.0 |
| Streptococcus pneumoniae ATCC 49619 |
0.12-0.5 |
| Neisseria gonorrhoeae ATCC 49226 |
0.25-1.0 |
Diffusion techniques
Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure (Ref2, Ref3) requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 30 µg tetracycline (class disk) or 30 µg minocycline to test the susceptibility of microorganisms to minocycline. Reports from the laboratory providing results of the standard single-disk susceptibility test with a 30-µg tetracycline or minocycline disk should be interpreted according to the following criteria:
For testing aerobic gram-negative microorganisms (Enterobacteriaceae), Acinetobacter
species and Staphylococcus aureus:
| Zone Diameter (mm) |
Interpretation |
| ≥ 19 |
Susceptible (S) |
| 15-18 |
Intermediate (I) |
| ≤ 14 |
Resistant (R) |
For testing Haemophilus influenzae5:
| Zone Diameter (mm) |
Interpretation |
| ≥ 29 |
Susceptible (S) |
| 26-28 |
Intermediate (I) |
| ≤ 25 |
Resistant (R) |
| 5 These zone diameter standards are applicable
only to susceptibility testing with Haemophilus influenzae using
Haemophilus Test Medium and a 30- µg tetracycline disk.Ref2 |
For testing Neisseria gonorrhoeae6:
| Zone Diameter (mm) |
Interpretation |
| ≥ 38 |
Susceptible (S) |
| 31-37 |
Intermediate (I) |
| ≤ 30 |
Resistant (R) |
| 6These interpretative standards
are applicable only to disk diffusion testing using GC agar and 1% growth
supplements, and a 30- µg tetracycline disk.Ref2 |
For testing Streptococcus pneumoniae7:
| Zone Diameter (mm) |
Interpretation |
| ≥ 23 |
Susceptible (S) |
| 19-22 |
Intermediate (I) |
| ≤ 18 |
Resistant (R) |
| 7 These interpretative standards are applicable
only to disk diffusion testing using Muller-Hinton agar adjusted with 5%
sheep blood and a 30-µg tetracycline disk.Ref2 |
For testing Vibrio cholerae8:
| Zone Diameter(mm) |
Interpretation |
| ≥ 19 |
Susceptible (S) |
| 15-18 |
Intermediate (I) |
| ≤ 14 |
Resistant (R) |
| 8 These interpretative standards are applicable
only to disk diffusion testing performed with a 30 µg tetracycline disk.(Ref2)
|
Interpretation should be as stated above for results using dilution techniques.
Interpretation involves correlation of the diameter obtained in the disk test
with the MIC for tetracycline.
As with standardized dilution techniques, diffusion methods require the use
of laboratory control microorganisms that are used to control the technical
aspects of the laboratory procedures. For the diffusion technique, the 30-µg
tetracycline or minocycline disk should provide the following zone diameters
in these laboratory test quality control strains:
| Microorganism |
Zone Diameter Range (mm) |
| Tetracycline |
Minocycline |
| Escherichia coli ATCC 2922 |
18-25 |
19-25 |
| Staphylococcus aureus ATCC 25923 |
24-30 |
25-30 |
| Haemophilus influenzae ATCC 49247 |
14-22 |
- |
| Neisseria gonorrhoeae ATCC 49226 |
30-42 |
- |
| Streptococcus pneumoniae ATCC 49619 |
27-31 |
- |
Animal Pharmacology And Toxicology
MINOCIN® minocycline HCl has been observed to cause a dark discoloration of the thyroid in experimental animals (rats, minipigs, dogs, and monkeys). In the rat, chronic treatment with minocycline hydrochloride has resulted in goiter accompanied by elevated radioactive iodine uptake and evidence of thyroid tumor production. Minocycline hydrochloride has also been found to produce thyroid hyperplasia in rats and dogs.
REFERENCES
Ref 1. National Committee for Clinical Laboratory Standards,
Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow
Aerobically-Fourth Edition; Approved Standard. NCCLS Document M7-A4, Vol. 17,
No. 2, NCCLS, 940 West Valley Road, Suite 1400, Wayne PA, January 1997.
Ref 2. National Committee for Clinical Laboratory Standards,
Performance Standards for Antimicrobial Disks Susceptibility Tests-Sixth Edition;
Approved Standard NCCLS Document M2-A6, Vol. 17, No. 1, NCCLS, 940 West Valley
Road, Suite 1400 Wayne, PA, January 1997.
Ref 3. National Committee for Clinical Laboratory Standards,
Performance Standards for Antimicrobial Susceptibility Testing-Eighth Edition;
Approved Standard NCCLS Document M100-S8, Vol.18, No.1, NCCLS, 940 West Valley
Road Suite 1400, Wayne PA, January 1998. This product's label may have been
updated. For current package insert and further product information, please
visit www.triaxpharma.com or call our toll-free number: 866-48-TRIAX (87429).
Call between 9:00 a.m. and 3:00 p.m. Eastern Time, Monday through Friday.
Last updated on RxList: 8/1/2008